Ketone peroxides are extensively used for the initiation of polymerization of ethylenically unsaturated compounds. Peroxides, however, have a tendency to be inflammable and explosive, with some exhibiting these properties to a greater extent than others. These properties carry with them obvious hazards to the users of the materials as well as to the manufacturers.
Many suggestions have been made to reduce the inflammability of ketone peroxides usually involving the incorporation of large quantities of water in the composition, the use of various additives and the use of particular solvents.
One typical prior art suggestion to provide safe ketone compositions is described in U.S. Pat. No. 3,330,871, wherein it is indicated that a class of "Safety Solvents" for for ketone peroxide may be used to provide compositions which exhibit resistance to ignition and once ignited burn mildly. A wide variety of solvents is mentioned including various glycols. However, it has been found that, while the compositions provided in the manner disclosed in this patent do indeed exhibit some resistance to ignition and once ignited burn mildly, after burning for a period of time, which may vary widely depending on the solvent used and the quantity present, the composition suddenly flares up and burns vigourously. The tendency of these prior art compositions to flare up suddenly is extremely hazardous to a user or manufacturer seeking to extinguish the ignited composition, since while the ignited composition may be burning mildly and the operator can approach the flame with suitable extinguishing equipment, before extinguishing the flame, a sudden flare up may occur, causing injury to the operator.